Making sense of temporally sparse hydrochemical data to support groundwater system conceptualisation in the Georgina Basin, Northern Territory and Queensland

This hydrochemical study contributes to a broader investigation of the hydrogeology and groundwater systems within the Georgina Basin, spanning the Northern Territory and Queensland. The regional investigation aimed to synthesise geoscience and hydrogeological datasets to inform a new whole-of-basin conceptualisation of groundwater systems and flow dynamics within the regional unconfined carbonate aquifers of the Georgina Basin. Within this context, this study evaluates hydrochemical data to support hydrogeological insights, addressing challenges relating to handling large datasets from multiple sources with variable temporal resolution. Hydrochemical data from groundwater bores, springs and rainfall have been compiled from past studies and publicly available datasets. A Python-based workflow has been developed to standardise data formats, manage data inconsistencies and examine the hydrochemistry data using a variety of visualisation tools. Despite poor temporal resolution, the extensive spatial coverage has enabled geostatistical techniques, particularly hierarchical cluster analysis (HCA) of major ions in groundwater, to identify four distinct hydrochemical clusters. Notably, a distinct cluster delineates areas of enhanced recharge associated with carbonate outcrop and along streams and floodout zones. Also, some Great Artesian Basin bores are part of the same cluster as the regional unconfined aquifers, indicating potential inter-aquifer connectivity. HCA has refined the interpretation of groundwater processes in the regional unconfined aquifers determined from groundwater levels, geological information and previous environmental tracer investigations. Using Python enables a more traceable and structured approach to handling hydrochemical datasets with variable quality. The integration of hydrochemical datasets with complementary hydrogeological data enhances confidence in interpretations of regional groundwater system dynamics. Presented at the 52nd Congress of International Association of Hydrogeologists (IAH2025)